PD-1 Expression Research Articles

Abstract A036: Next gen liquid biopsy: Comprehensive analysis from a single tube of blood

Abstract Introduction There remains a largely untapped potential for utilizing liquid biopsy as a non- invasive, real-time window into tumor biology. In this study, we report on the use of the high- multiplex protein quantitation capability of the OrionTM spatial biology platform (RareCyte®, Inc) and cell picking capability of the CyteFinder® rare cell platform, to perform a comprehensive liquid biopsy analysis of whole blood that provides a deeper understanding of samples. This novel technology was used to characterize circulating tumor cells (CTCs), perform immune profiling of white blood cells (WBCs), and perform targeted mutation profiling of CTCs and cell-free DNA (cfDNA). All of these analytes can be measured from one 7.5 mL draw of blood. This array of tests was applied to cancer samples to demonstrate clinical feasibility. MethodsBlood samples were collected into AccuCyte® blood collection tubes. Buffy coats were processed to microscope slides using AccuCyte® blood processing kits. Slides were fixed and stained with an 18-plex immuno-oncology panel and imaged using the Orion Spatial Biology platform to evaluate protein biomarker expression on CTCs and to profile WBCs. Individual CTCs and WBCs from clinical samples were isolated using the CytePicker® for downstream molecular analysis. cfDNA was isolated from plasma collected during the AccuCyte process. Picked CTCs, WBCs, and cfDNA were sequenced using the CleanPlex® OncoZoom® Cancer Hotspot Kit. ResultsCancer patient blood was tested with a high-plex immunofluorescence assay using the Orion spatial biology system. CTCs were identified and phenotypically characterized in multiple cancer types. On the same slides, immunophenotyping of WBCs was performed. T- cell, B-cell, and macrophage populations were quantified. Additional sub-populations of T-cells (regulatory and memory) and proliferating cells (Ki67+) were enumerated. Expression of checkpoint-specific markers PD-L1 and PD-1 was measured on CTCs and WBCs. Sequencing results from individual picked CTCs showed evidence of minor clones representative of tumor heterogeneity that were not detectable in the cfDNA analysis. Conclusions This novel application of a high-plex spatial biology imaging system to liquid biopsies, in conjunction with the proven capabilities of rare cell detection and genomic analysis of single cells and cfDNA, has the potential to revolutionize liquid biopsy testing. From a single blood sample, this approach allows one to ask important questions about the complex interactions between the immune system and the tumor and to follow these interactions longitudinally in real time over the course of the disease. The goal is to leverage this unprecedented depth of analysis to improve patient outcomes and better understand the biological complexity of disease. Future directions of this work are to study rare types of WBCs that indicate immune activation and response to the tumor, and the detection and longitudinal monitoring of cell therapies such as CAR T cells after infusion. Citation Format: Arturo B Ramirez, Jon Ladd, Erin Bayer, Brock Bartels, Rachel Ponting, Arista Tischner. Next gen liquid biopsy: Comprehensive analysis from a single tube of blood [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr A036.

Abstract 4138339: Abatacept prevents anti-PD-1-induced inflammatory heart failure development after myocardial ischemic injury in mice

Introduction: Immune checkpoint inhibitors (ICI), such as anti-PD-1 monoclonal antibodies are increasingly used in anti-cancer therapy. However, several cardiovascular adverse effects can occur with the use of ICIs, including new-onset heart failure. Hypothesis: We hypothesized that prior myocardial ischemic injury could exacerbate cardiac dysfunction and inflammation caused by anti-PD-1 treatment. Moreover, we investigated whether abatacept, a T-cell co-stimulation blocker, can prevent ICI-induced cardiac effects. Methods: To induce reversible cardiac ischemia, C57Bl/6J mice were treated with isoprenaline (ISOP group) or with PBS (CON group), followed by 16 weeks of recovery period. Following this, mice from both groups were divided into three further treatment groups: isotype control, anti-PD-1, or anti-PD-1 combined with abatacept, and were treated for two weeks, with three weekly intraperitoneal injections. Echocardiography was performed to evaluate cardiac function while myocardial inflammation was assessed by qRT-PCR and immunohistochemistry. Flow cytometry and Western blot were used to investigate changes occurring in the thymus. Results: Mice with normal heart function but with prior ischemic injury and anti-PD-1 treatment (ISOP + anti-PD-1) showed significantly decreased fractional shortening and cardiac index on echocardiography, while in animals with abatacept co-treatment (ISOP+anti-PD-1+abatacept) cardiac function was not altered. Increased immune cell infiltration was seen in the myocardium of the ISOP+anti-PD-1 treated group compared to CON animals, including T-cells and macrophages, with increased expression of pro-inflammatory cytokines, while co-treatment with abatacept ameliorated the inflammatory response. In the thymus, increased expression of PD-1 was found after abatacept co-treatment. Conclusion: Prior myocardial ischemic injury was associated with cardiac dysfunction and inflammation after anti-PD-1 treatment, which was ameliorated by abatacept co-treatment. Patients with prior cardiac ischemic events may be at greater risk for developing ICI-induced cardiotoxicity, including new-onset HF.

BIOM-57. PERITUMORAL EDEMA AS A PREDICTOR OF PD-1 EXPRESSION IN BRAIN METASTASES

Abstract Brain metastases represent a significant problem in oncology with associated high morbidity and mortality. They have been associated with increased peritumoral edema which can worsen neurological symptoms and patient outcomes. Peritumoral cerebral edema may be an important metric of interest as some MRI studies have suggested an association between molecular factors and peritumoral edema. We hypothesized that an association exists between PD-1 expression in brain mets from NSCLC and the radiographic peritumoral edema to enhancing tumor ratio (ETR). A retrospective analysis of tumor characteristics was conducted to identify patients with brain metastases from non-small cell lung cancer. Patients were stratified into three groups based on their tumor PD-1 expression levels: 0%, 1-49%, and 50% or higher. Tumor and edema volumes were measured in these patients using MRIs at the time of diagnosis and converted into edema to tumor ratios. Radiographic analysis has been completed for 19 patients with 9 having no PD-1 expression, 5 having low PD-1 expression, and 5 having high PD-1 expression. The no expression group had an average ETR of 3.02 while the low expression group had an average of 15.85 and the high expression group had an average of 9.12. These initial results show increased peritumoral edema in tumors with PD-1 expression when compared to tumors with no PD-1 expression, with a non-significant trend in favor of increased edema to tumor ratio (p = 0.055). The current project is ongoing with plans to expand patient cohorts to affirm or rule out significant ETR association by MRI.

EXTH-85. ASSESSMENT OF ANTI-CD69 ANTIBODY THERAPY ALONE OR IN COMBINATION WITH ANTI-PD-1 IN MURINE GBM

Abstract BACKGROUND Glioblastoma multiforme (GBM) is an aggressive central nervous system malignancy with a dismal prognosis. There is continued interest in trying multiple immunotherapy modalities for this intractable cancer. Cluster of differentiation 69 (CD69), is an early marker of T and NK cell activation. CD69 play multiple roles in T cell-mediated immunoregulation with immune inhibitory role in antitumor immunity. Previous preclinical work in non-CNS malignancies has demonstrated that targeting CD69 can improve clinical outcome and anti-tumor immunity. We aimed to assess anti-CD69 Ab therapy alone or in combination with anti-PD-1 in murine GBM. METHODS We explored transcriptomic data from 163 GBM patients using the TCGA database. We then tested the therapeutic value of anti-CD69 immunotherapy in a preclinical model of GBM and assessed the ideal timing of treatment with anti-CD69 Ab by evaluating survival and immune tumor-microenvironment by flow cytometry. Two treatment-timings with anti-CD69 Ab were further evaluated either alone, or in combination with anti-PD1 Abs and compared to control and to anti-PD1 only treatment. Survival data was collected. RESULTS CD69 expression was significantly increased in GBM patients tissues as compared with normal brains and increased CD69 expression was associated with worse progression-free survival. Treatment-timing with single dose anti-CD69 Ab at day 1 or three doses at days 4, 8 and 12 post tumor-injection minimally improved the median survival time of animals. In addition, effective CD69 blockage and significantly elevated PD-1 expression on NK cells was found in these timings, making them good candidates to evaluate anti-CD69 Ab therapy alone or in combination with anti-PD-1 Ab. However, when assessing these treatment-timings with anti-CD69 Ab alone or in combination with anti-PD1 no survival benefit was found. CONCLUSION This is the first study assessing anti-CD69 Ab therapy alone or in combination with anti-PD-1 in murine GBM. While some effect was found on the cellular level, this didn’t translate to survival benefit and results are overall negative.

TMED inhibition suppresses cell surface PD-1 expression and overcomes T cell dysfunction

BackgroundBlockade of the programmed cell death protein 1 (PD-1) immune checkpoint (ICB) is revolutionizing cancer therapy, but little is known about the mechanisms governing its expression on CD8 T cells....

Spatial context of immune checkpoints as predictors of overall survival in patients with resectable colorectal cancer independent of standard TNM stages.

While immune checkpoint blockade (ICB) therapy has shown promising results in a small subset of colorectal cancer patients with high microsatellite instability (MSI-H), the majority of patients with colorectal cancer do not respond to ICB therapy. The main obstacle to the success of immunotherapy in cancer treatment is the exhaustion of tumor-infiltrating lymphocytes (TILs). Elucidating the spatial organization of immune checkpoints within the tumor microenvironment could pave the way for the development of novel prognostic tools and therapeutic strategies to enhance antitumor immune responses. To clarify the spatial and functional diversity of tumor-infiltrating lymphocytes (TILs) in the colorectal tumor microenvironment (TME), we performed multiplexed IHC to examine the exhaustion of TILs in the TME (the expression of PD-1 and TIM-3 (T-cell immunoglobulin and mucin-domain-containing protein 3), which are major biomarkers of T-cell exhaustion) and Lasso-Cox analyses of the correlation between CRC prognosis and TME features. For proof of concept, the antitumor efficacy of TIM-3 and PD-1 dual blockade in CRC was further evaluated in a CT26 subcutaneous tumor model of human CRC. We found that the spatial context of PD-1 and TIM-3 successfully predicted the overall survival of CRC patients independent of TNM stage. Dual targeting of PD-1 and TIM-3 in mouse tumor models inhibited tumor progression and reduced T-cell exhaustion, indicating a potential strategy for improving the clinical treatment of CRC.

Apolipoprotein A1-encoding recombinant adenovirus remodels cholesterol metabolism in tumors and the tumor microenvironment to inhibit hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent malignant tumor requiring effective treatments. Oncolytic viruses induce anti-tumor responses but have limited efficacy. Apolipoprotein A1 (ApoA1) inhibits inflammation, modulates immunity, and promotes anti-oxidation. This study aims to construct an oncolytic adenovirus (Ad5)-ApoA1 for superior anti-tumor effects.We analyzed ApoA1 expression in tumors and its prognostic significance using public databases. Subsequently, we engineered a recombinant oncolytic adenovirus Ad5-ApoA1 and assessed its replication and oncolytic efficacy in vitro and in nude mice. The impact of Ad5-ApoA1 on the tumor microenvironment of HCC was evaluated through flow cytometry, transcriptome sequencing, single-cell sequencing, and other methodologies. Additionally, mechanisms of immune microenvironment modulation by Ad5-ApoA1 were explored. ApoA1 expression was down-regulated with HCC progression and significantly positively correlated with the prognosis of HCC patients. Ad5-ApoA1 exhibited robust oncolytic activity but showed no therapeutic effect on nude mice. However, it significantly inhibited HCC growth and prolonged the survival period of both healthy-immune and humanized immune-reconstituted NCG mice. Furthermore, Ad5-ApoA1 significantly promoted the expression of IFN-γ and GzmB in CD8+ T cells while inhibiting the expression of PD-1 and LAG-3. Notably, the cholesterol content in the CD8+ T cells studied was significantly correlated with the expression of PD-1 and LAG-3, with ApoA1 promoting cholesterol efflux and reducing cholesterol levels. Ad5-ApoA1 activates CD8+ T cells by promoting large-scale viral replication. High levels of ApoA1 protein expression promote cholesterol efflux, inhibit CD8+ T cell depletion, and reduce inflammatory factors, ultimately leading to superior therapeutic effects on hepatocellular carcinoma.

Human GM-CSF/IL-3 enhance tumor immune infiltration in humanized HCC patient-derived xenografts

Background & AimsResponses to immunotherapies in hepatocellular carcinoma (HCC) are suboptimal with no biomarkers to guide patient selection. “Humanized” mice represent promising models to address this deficiency but are limited by variable chimerism and underdeveloped myeloid compartments. We hypothesized that expression of human GM-CSF and IL-3 increases tumor immune cell infiltration, especially myeloid-derived cells, in humanized HCC patient-derived xenografts (PDXs). Material and MethodsNOG (NOD/Shi-scid/IL-2Rγnull) and NOG-EXL (huGM-CSF/huIL-3 NOG) mice conditioned with Busulfan underwent i.v. injection of human CD34+ cells. HCC PDX tumors were then implanted subcutaneously (SQ) or orthotopically (OT). Following serial blood sampling, mice were euthanized at defined tumor sizes. Tumor, blood, liver, and spleen were analyzed by flow cytometry and immunohistochemistry. ResultsHumanized NOG-EXL mice demonstrated earlier and increased human chimerism compared to humanized NOG mice (82.1% vs 43.8%, p<0.0001) with increased proportion of human monocytes (3.2% vs 1.1%, p=0.001) and neutrophils (0.8% vs 0.3%, p=0.02) in circulation. HCC tumors in humanized NOG-EXL mice had increased human immune cell infiltration (57.6% vs 30.2%, p=0.04), noting increased regulatory T cells (14.6% vs 6.8%, p=0.04), CD4+ PD-1 expression (84.7% vs 32.0%, p<0.01), macrophages (1.2% vs 0.6%, p=0.02), and neutrophils (0.5% vs 0.1%, p<0.0001). No differences were observed in tumor engraftment or growth latency in SQ tumors, but OT tumors required implantation at two rather than four weeks post-humanization for successful engraftment. Finally, utilizing adult bone marrow instead of fetal livers enabled partial HLA-matching to HCC tumors but required more CD34+ cells. ConclusionsHuman GM-CSF and IL-3 expression in humanized mice resulted in features more closely approximating the immune microenvironment of human disease, providing a promising model for investigating critical questions in immunotherapy for HCC. Impact and ImplicationsThis study introduces a unique mouse model at a critical point in the evolution of treatment paradigms for patients with hepatocellular carcinoma (HCC). Immunotherapies have become first line treatment for advanced HCC; however, response rates remain low with no clear predictors of response to guide patient selection. In this context, animal models that recapitulate human disease are greatly needed. Leveraging xenograft tumors derived from patients with advanced HCCs and a commercially available immunodeficient mouse strain that expresses human GM-CSF and IL-3, we demonstrate a novel but accessible approach for modeling the HCC tumor microenvironment.

LAG-3 Expression, γδ-T cell/MHC-I Interactions and Prognosis in Merkel Cell Carcinoma

Merkel Cell Carcinoma (MCC) is an aggressive cutaneous malignancy with a poor prognosis. One of the major mechanisms of immune evasion in MCC involves downregulation of MHC-I. Anti-PD-1/PD-L1 checkpoint inhibitors (CKIs) have revolutionized treatment for MCC, producing objective responses in ∼50% of patients, and are now standard of care; however, a substantial proportion of patients either fail to respond or develop resistance to CKIs. Given these recent successes, identification of other targetable immune checkpoints in the MCC tumor microenvironment (TME) is of great interest. Additionally, γ-delta (γδ) T cells may play critical roles in the response to MHC-I deficient cancers; therefore, evaluating γδ-T cells as a prognostic biomarker is warranted. We characterized the expression of PD-L1, PD-1, CD3, CD8, LAG-3, MHC-I, and γδ-T cells by IHC in a pre-immunotherapy retrospective cohort of 54 cases of MCC, and quantified expression levels and marker density via HALO. The increased density of LAG-3 and γδ-T cells correlated with other markers of an inflamed TME, with significant positive associations across all six markers (p<.002). Reflective of their putative role in the response to MHC-I suppressed cancers, cases with low HLA-I density showed a trend towards a higher ratio of γδ-T cells:CD3+ T cells (Spearman's r=-0.1582, p=0.21). Importantly, high CD3 density (HR=0.23, p=0.002), LAG-3 density (HR=0.47, p=0.037), γδ-T cell density (HR=0.26, p=0.02), and CD8 density (HR=0.27, p=0.03) showed associations with improved progression-free survival. Conditional tree analysis demonstrated that high CD8 and TCRδ expression were non-significant predictors of improved PFS and OS. Overall, LAG-3 is expressed in MCC infiltrates and is prognostic in pre-immunotherapy MCC, suggesting a potential role for LAG-3 inhibition in MCC. Additionally, CD8 and γδ-T cells may play a critical role in the response to MCC, and γδ-T cell density may represent a novel biomarker in MCC.

The role of PD-1/PD-L1 pathway in ulcerative colitis and changes following tonsil-derived mesenchymal stem cells treatment

Background/Aims: The programmed death 1 (PD-1)/programmed death-ligand 1 (PD-L1) pathway has not been fully evaluated in inflammatory bowel disease. We evaluated PD-1/PD-L1 levels in patients with ulcerative colitis (UC) and their significance in tonsil-derived mesenchymal stem cells (TMSCs) treatment.Methods: Using acute and chronic murine colitis model, we measured the PD-1 and PD-L1 levels in inflamed colonic tissues pre- and post-treatment with TMSCs. We also measured PD-1 and PD-L1 levels in colonic tissues from UC patients, compared to normal controls.Results: In the analysis using human colonic tissues, a significant increase in the levels of PD-1 and PD-L1 was observed in the colonic mucosa of patients with UC compared with normal controls (&lt;i&gt;p&lt;/i&gt; &lt; 0.001 and &lt;i&gt;p&lt;/i&gt; = 0.005, respectively). When comparing the maximal disease extent, PD-L1 levels were highest in patients with proctitis (38.5 ± 46.7), followed by left-side colitis (17.5 ± 23.1) and extensive colitis (5.2 ± 8.2) (&lt;i&gt;p&lt;/i&gt; &lt; 0.001). In the chronic colitis model, the level of PD-L1 was decreased (&lt;i&gt;p&lt;/i&gt; = 0.040) and the level of PD-1 increased more than in normal controls (&lt;i&gt;p&lt;/i&gt; = 0.047). After treatment with TMSC, significant improvements were observed in body weight, disease activity index, and colon length recovery. Additionally, the levels of PD-1 and PD-L1 were recovered; PD-L1 significantly increased (&lt;i&gt;p&lt;/i&gt; = 0.031), while the level of PD-1 decreased (&lt;i&gt;p&lt;/i&gt; = 0.310).Conclusions: The altered expression of PD-1 and PD-L1 in colonic mucosa may be a possible mechanism of UC, and T-MSC-derived PD-L1 could help suppress colitis.

Spatial multiplex analysis of lung cancer reveals that regulatory T cells attenuate KRAS-G12C inhibitor-induced immune responses.

Kirsten rat sarcoma virus (KRAS)-G12C inhibition causes remodeling of the lung tumor immune microenvironment and synergistic responses to anti-PD-1 treatment, but only in T cell infiltrated tumors. To investigate mechanisms that restrain combination immunotherapy sensitivity in immune-excluded tumors, we used imaging mass cytometry to explore cellular distribution in an immune-evasive KRAS mutant lung cancer model. Cellular spatial pattern characterization revealed a community where CD4+ and CD8+ T cells and dendritic cells were gathered, suggesting localized T cell activation. KRAS-G12C inhibition led to increased PD-1 expression, proliferation, and cytotoxicity of CD8+ T cells, and CXCL9 expression by dendritic cells, indicating an effector response. However, suppressive regulatory T cells (Tregs) were also found in frequent contact with effector T cells within this community. Lung adenocarcinoma clinical samples showed similar communities. Depleting Tregs led to enhanced tumor control in combination with anti-PD-1 and KRAS-G12C inhibitor. Combining Treg depletion with KRAS inhibition shows therapeutic potential for increasing antitumoral immune responses.

Unravelling the Reasons Behind Limited Response to Anti-PD Therapy in ATC: A Comprehensive Evaluation of Tumor-Infiltrating Immune Cells and Checkpoints.

Inhibiting the immune checkpoint (ICP) PD-1 based on PD-L1 expression status has revolutionized the treatment of various cancers, yet its efficacy in anaplastic thyroid carcinoma (ATC) remains limited. The therapeutic response depends upon multiple factors, particularly the conduciveness of the tumor's immune milieu. This study comprehensively evaluated and classified ATC's immune microenvironment (IME) to elucidate the factors behind suboptimal response to anti-PD therapy. Utilizing multiplex-immunofluorescence and immunohistochemistry, we retrospectively analyzed 26 cases of ATC for expression of ICPs PD-L1, PD-1, CTLA4, TIM3, and Galectin-9 and tumor-infiltrating cytotoxic T lymphocytes (CTL)-the effector cells, the anti-tumor NK cells, the immune-inhibitory myeloid-derived suppressor (MDSC) and regulatory T (Treg) cells, and B lymphocytes. Most ATCs (65%) exhibited PD-L1 positivity, but only 31%, in addition, had abundant CTL (type I IME), a combination associated with a better response to ICP inhibition. Additionally, PD-1 expression levels on CTL were low/absent in most cases-a "target-missing" situation-unfavorable for an adequate therapeutic response. All but one ATC showed nuclear Galectin-9 expression. The documentation of nuclear expression of Galectin-9 akin to benign thyroid is a first, and its role in ATC pathobiology needs further elucidation. In addition to less abundant PD-1 expression on CTL, the presence of MDSC, Treg, and exhausted cytotoxic T lymphocytes in the immune milieu of ATC can contribute to anti-PD resistance. TIM3, the most frequently expressed ICP on CTL, followed by CTLA4, provides alternate therapeutic targets in ATC. The co-expression of multiple immune checkpoints is of great interest for ATC since these data also open the avenue for combination therapies.

T cell and soluble co-inhibitory receptor expression in patients with visceral leishmaniasis are markers of treatment response and clinical outcome

Abstract Background Co-inhibitory receptors (immune checkpoints) regulate activated immune cells. Their expression on T cells can limit host defense. We hypothesized that chronic Leishmania donovani infection in patients with visceral leishmaniasis (VL) leads to expression of co-inhibitory receptors that could be markers of treatment response and clinical outcome. Method A prospective cohort of 21 subjects with VL (7 with HIV coinfection) and 10 controls was established to measure T cell expression of co-inhibitory receptors (PD-1, Tim-3, LAG-3, CTLA-4, and TIGIT) by flow cytometry in discarded remnants of diagnostic splenic or bone marrow aspirates and peripheral blood collected before and after treatment. Plasma levels of soluble co-inhibitory proteins (sPD-1, sTim-3, sLAG-3, and sCTLA-4), and selected cytokines were determined by immunoassay. Results Expression of co-inhibitory receptors in peripheral blood T cells generally reflected findings in spleen and bone marrow aspirates. PD-1 and Tim-3 were upregulated in CD4+ T cells in HIV-negative and HIV-positive subjects with VL compared to controls. CD8+ T cells from HIV-negative subjects with VL displayed a similar pattern. Plasma levels of sPD-1 and sTim-3 were also greater in VL patients than controls. CD8+ and CD4+ T cells co-expressing PD-1 and Tim-3 showed considerable decline with treatment. Mortality in HIV-negative VL patients was associated with increased CD8+ T cells co-expressing Tim-3 and PD-1, triple positive CD4+ and CD8+ T cells (PD-1+Tim-3+LAG-3+), and elevated sLAG3. Conclusion Tim-3 and PD-1 expression on CD4+ and CD8+ T cells, and increased plasma sLAG-3, were markers of treatment response and clinical outcome in patients with VL.

Altered immunophenotypic expression in the peripheral bladder cancer immune landscape.

Treatments targeting the immune system only benefit a subset of patients with bladder cancer (BC). Biomarkers predictive of BC progression and response to specific therapeutic interventions are required. We evaluated whether peripheral blood immune subsets and expression of clinically relevant immune checkpoint markers are associated with clinicopathologic features of BC. Peripheral blood mononuclear cells isolated from blood collected from 23 patients with BC and 9 age-matched unaffected-by-cancer control donors were assessed using a 21-parameter flow cytometry panel composed of markers of T, B, natural killer and myeloid populations and immune checkpoint markers. Patients with BC had significantly lower numbers of circulating CD19+ B cells and elevated circulating CD4+CD8+ Tcells compared with the control cohort. Immune checkpoint markers programmed cell death protein 1 (PD-1) and T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) were elevated in the total peripheral immune cell population in patients with BC. Within the BC cohort, PD-1 expression in T and myeloid cells was elevated in muscle-invasive compared with non-muscle-invasive disease. In addition, elevated T, B and myeloid PD-1 cell surface expression was significantly associated with tumor stage, suggesting that measures of peripheral immune cell exhaustion may be a predictor of tumor progression in BC. Finally, positive correlations between expression levels of the various immune checkpoints both overall and within key peripheral blood immune subsets collected from patients with BC were observed, highlighting likely coregulation of peripheral immune checkpoint expression. The peripheral blood immunophenotype in patients with BC is altered compared with cancer-free individuals. Understanding this dysregulated immune profile will contribute to the identification of diagnostic and prognostic indicators to guide effective immune-targeted, personalized treatments.

Increased PD-1/PD-L1 Immune Checkpoint Expression Is Associated With Oral Squamous Cell Carcinoma in Never-Smokers and Never-Drinkers.

This study aimed to explore the disparities in PD-1 and PD-L1 expression among oral squamous cell carcinomas (OSCCs) in individuals categorized as never-smokers/never-drinkers versus smokers/drinkers. Immunohistochemical staining for PD-1 and PD-L1, along with PDCD1LG2/cen9 dual color probe analysis, was conducted on 130 OSCC specimens from both smoker/drinker and never-smoker/never-drinker cohorts. Associations between smoking/drinking status, clinicopathologic data, immunohistochemical antibody expression, fluorescence insitu hybridization, and survival outcomes were assessed. OSCC in never-smokers/never-drinkers exhibited significantly elevated PD-1 expression (p = 0.003), increased PD-L1-TPS expression (p = 0.044), and elevated PD-L1-CPS expression (p < 0.001). High PD-L1-ICS expression was more prevalent in never-smokers (p = 0.042). Moreover, never-smokers and never-drinkers demonstrated augmented PD-L1 gene copy numbers (p = 0.081 and p = 0.054, respectively). Increased PD-L1 gene copy number, particularly amplification, correlated with PD-L1-TPS (p = 0.039 and p < 0.001). Conversely, PD-L1 gene copy loss was associated with negative PD-L1-CPS (p = 0.023). Notably, positive PD-L1-CPS was significantly linked with improved overall survival (p = 0.023). OSCC arising in never-smokers/never-drinkers exhibit heightened PD-1/PD-L1 signaling, suggesting potential efficacy of immune checkpoint therapy in this subgroup of tumors.

High PD-1 and CTLA-4 expression correlates with host immune suppression in patients and a mouse model infected with Echinococcus multilocularis

BackgroundAlveolar echinococcosis (AE), a fatal disease caused by Echinococcus multilocularis, often affects the liver, with tumor-like growth. However, the mechanism by which E. multilocularis evades host immune surveillance remains unclear.MethodsWe collected liver specimens from hepatic alveolar echinococcosis (HAE) patients and established a mouse model of E. multilocularis infection. Immunofluorescence staining and flow cytometry were performed to analyze programmed cell death protein 1 (PD-1) and cytotoxic T lymphocyte associated antigen 4 (CTLA-4) expression in human samples, while flow cytometry and quantitative real-time polymerase chain reaction (PCR) were performed for similar analyses in mouse samples. Cell proliferation and protoscolex (PSC) killing assays were designed to explore how E. multilocularis induces host immunosuppression.ResultsAn inflammatory reaction band with high PD-1 and CTLA-4 expression was found in close liver tissue (CLT). The ratio of regulatory T cells (Tregs) was higher in CLT than in distant liver tissue (DLT), and Tregs in CLT tended to express higher levels of PD-1 and CTLA-4 than those in DLT from HAE patients. Echinococcus multilocularis-infected mice showed significantly elevated expression of PD-1 and CTLA-4 on splenocytes and peritoneal cells. PD-1/PD-L1 or CTLA-4 pathway blockade could relieve the immunosuppressive effects of Tregs from infected mice and enhance PSC killing by mouse splenocytes.ConclusionsE. multilocularis regulated the function of T cells via the PD-1/PD-L1- and CTLA-4-dependent pathways and subsequently evaded host immune attacks. These findings provide insights for investigating the pathogenic mechanism of AE.Graphical

Study on correlation between CXCL13 and prognosis and immune characteristics of ovarian cancer.

Ovarian cancer (OC) has a limited immunotherapeutic response; hence, this study aimed to investigate the relationship between CXC-chemokine ligand 13 (CXCL13) expression and overall survival (OS) rate, key immune pathways, degree of immune cell infiltration, and progressive disease (PD)-1 checkpoint blockade. A total of 703 differentially expressed genes were obtained from "The Cancer Genome Atlas" (TCGA) database based on the immune and stromal scores of 379 OC patients for getting the targeted gene CXCL13. The association between CXCL13 and OS in OC patients, biological function annotation of CXCL13, and its correlation with immune components were assessed. The results indicated that upregulated CXCL13 expression was positively correlated with better OC patient prognosis. CXCL13 expression was associated with 6 immune-related pathways, 10 immune cells, and PD-1 expression of OC micro-environment. Moreover, high expression of CXCL13 was related to a better tumor response and more extended tumor-stable stage after PD-1 blocking therapy in IMvigor210. The study concluded that CXCL13 could be a prognostic marker and a potential immunotherapy target for OC patients, especially PD-1 checkpoint blockade.

How Co-Stimulatory/Inhibitory Molecules Vary Across Immune Cell Subtypes in the Severity of Systemic Lupus Erythematosus Compared to Controls

Background: Co-stimulatory and co-inhibitory molecules are critical to T cell responses and involved in the pathogenesis of systemic lupus erythematosus (SLE). This study aimed to comprehensively analyze the surface expression of these molecules in various phenotypic immune cells, comparing the differences between various levels of the severity in SLE and control groups. Methods: Peripheral blood mononuclear cells (PBMCs) were isolated using Ficoll-Paque from blood samples of severe SLE patients (treatment with immunosuppressants), mild SLE patients (excluding those with persistent proteinuria or thrombocytopenia), and healthy controls (n = 10 each). PBMCs were stimulated for 48 h. The cells were stained with anti-CD3, CD4, CD28, PD-1, and CTLA-4 antibodies and analyzed by flow cytometry. Differences between groups were assessed using the Kruskal–Wallis test and Mann–Whitney U-test, with median values and statistical significance (p &lt; 0.05) reported. Results: The results showed that CD28 expression was significantly higher in SLE patients compared to controls, with the highest levels in mild SLE. However, CD3+ CD28+ and CD4+ CD28+ cells were more prevalent in controls (p = 0.032 and 0.017, respectively). Mild SLE patients exhibited the highest CTLA-4 expression, with significant differences from severe SLE and controls (p = 0.030 and 0.037, respectively). PD-1 expression was lowest in severe SLE but highest in mild SLE within CD3+ CD4+ cells (p = 0.001). After 48 h of activation, CD4+ CTLA4+ and CD3+ CTLA4+ expression levels were significantly higher in controls compared to SLE groups. Conclusions: Our study highlighted that the expression of CD28, CTLA-4, and PD-1 in lymphocytes and specific T cell subsets was various according the severity of SLE in patients, underscoring their roles in disease pathogenesis.

A splicing isoform of PD-1 promotes tumor progression as a potential immune checkpoint

The immune checkpoint receptor, programmed cell death 1 (PD-1, encoded by PDCD1), mediates the immune escape of cancer, but whether PD-1 splicing isoforms contribute to this process is still unclear. Here, we identify an alternative splicing isoform of human PD-1, which carries a 28-base pairs extension retained from 5′ region of intron 2 (PD-1^28), is expressed in peripheral T cells and tumor infiltrating lymphocytes. PD-1^28 expression is induced on T cells upon activation and is regulated by an RNA binding protein, TAF15. Functionally, PD-1^28 inhibits T cell proliferation, cytokine production, and tumor cell killing in vitro. In vivo, T cell-specific exogenous expression of PD-1^28 promotes tumor growth in both a syngeneic mouse tumor model and humanized NOG mice inoculated with human lung cancer cells. Our study thus demonstrates that PD-1^28 functions as an immune checkpoint, and may contribute to resistance to immune checkpoint blockade therapy.

The prognostic and therapeutic value of the tumor microenvironment and immune checkpoints in pancreatic neuroendocrine neoplasms

Pancreatic neuroendocrine neoplasms (Pan-NEN) represent a group of highly heterogeneous cancers, characterized by complex and diverse biological behavior. The objective of this study was to systematically investigate the immunological features of the tumor microenvironment (TME) in Pan-NEN, aiming to identify prognostic biomarkers and explore the therapeutic potential of immunotherapy for Pan-NEN. Tumor and adjacent normal tissues were collected from 56 patients with Pan-NEN. Immunohistochemical analysis was conducted on tumor tissues using a panel of monoclonal antibodies targeting key immune markers. The expression levels of these markers were quantitatively assessed and correlated with clinicopathological features and overall survival. Low expression of CD3, CD8, CD4, CD68, CD163, Foxp3, CD56, CD69, GZMB, HLA-1, HLA-II, PD-1, and PD-L1 were observed in the majority of Pan-NEN patient samples. PD-1 expression was positively correlated with CD4 and Foxp3 expression, while PD-L1 expression was positively correlated with CD68, CD163, and Foxp3 expression; HLA-II expression was positively correlated with GZMB expression. Infiltration of lymphocytes (CD3 + or CD8+) and macrophages (CD68 + or CD163+) and expression of PD-1/PD-L1 were more pronounced in poorly differentiated neuroendocrine carcinoma (Pan-NEC) compared to well-differentiated neuroendocrine tumors (Pan-NET), while CD68 and PD-L1 correlated with advanced disease stage. Conversely, HLA-I antigen expression was commonly downregulated in Pan-NEC. Univariate Cox proportional hazard analysis demonstrated that tumor grade, stage; CD4+, CD68+, and CD163 + cell count; and expression of PD-1 and PD-L1 were significantly associated with poor survival outcomes, while the positive expression of HLA-I was correlated with a more favorable survival prognosis. Furthermore, multivariate Cox proportional hazard analyses revealed that tumor grade, stage, and PD-1 expression are independent prognostic factors. The immunological landscape of Pan-NEN offers potential prognostic value and therapeutic targets. The findings suggest that immunotherapy, particularly targeting the PD-1/PD-L1 pathway, may serve as a promising strategy for the treatment of Pan-NEN, especially for Pan-NEC patients.